What We Know So Far

Two boaters rescued after spending the night run aground near Whitsunday Island

Isolated rainfalls of up to 940mm in two days in some locations

1,300km of coastline is on Flood Watch

More than 63,000 homes are without power

The Defence Force and emergency service personnel have started moving into some of the worst affected towns to provide relief, but residents are being warned to stay off the road unless absolutely necessary

Two people have had to be rescued after getting trapped in their vehicles driving through floodwaters, Queensland Fire and Emergency Services Commissioner Katarina Carroll said.

Fairfax Media / Brian Cassey
Cyclone Debbie ripped the roof off this house in Bowen.
"If you do not have to be on the roads until Friday, please stay off the roads," the Premier told locals in a press conference on Wednesday morning.

Cyclone Debbie was downgraded to a tropical low in the early hours of Wednesday morning, as heavy rains, damaging wind gusts and high tides continue to strike.

The towns of Bowen, Airlie Beach and Proserpine have been worst affected by the cyclone, which brought 260km/h wind gusts and major flooding along the coastline.

The Bruce Highway, the main arterial to the area, has been cut off by flash flooding near Bowen and is closed to all traffic, according to the Queensland Department of Transport and Main Roads website.

Flooding and damage to roads have left Bowen, Airlie Beach and Proserpine completely cut off, with access only possible via water.

Department of Transport and Main Roads
Road closures have left Proserpine, Bowen and Airlie Beach completely cut off.

Queensland Police are accessing Airlie Beach via boats later today and the Army is sending in an amphibious vehicle, according to the ABC.

No reports of fatalities have been reported, although there are multiple reports of serious injuries.

Prime Minister Malcolm Turnbull says he is working closely with the Queensland Government to respond to the crisis, with more than 1,000 emergency services and defence personnel starting work on the clean-up.

"As the day progresses, we will get an understanding of the damage from the storm," he said this morning.

"Nature has flung her worst at the people of North Queensland and it's now our job to make sure that every agency pulls together and, indeed, the private sector -- particularly the banks and insurance companies -- pull together to provide support to the people of North Queensland."

The wild weather isn't over yet. The Bureau of Meteorology has warned of continued very heavy rain and wind on the Central Coast, Whitsundays and Central Highlands regions. Locals will continue to be battered by wind gusts of up to 120km/h in areas north of Emerald to St Lawrence.

But it is flooding that is now the major threat to local communities. The Bureau of Meteorology has warned that continuing rain -- on top of the up to 500mm measured during the height of the cyclone -- was putting catchments at risk of overflowing.

More than 1,300km of coastline, from the town of Ayr right down to the New South Wales border, is on Flood Watch.

Moderate flood levels are likely at Mackay on Wednesday, and major flood levels are expected to continue to rise at Mirani, the BOM said.

"As the rainfall moves further inland the catchments at risk from Wednesday include Fitzroy, Belyando and Suttor (Burdekin River catchment), upper Thomson and upper Barcoo Rivers," the BOM's Flood Watch statement read.

"Rainfall is expected to extend into south east Queensland during Thursday, with widespread rainfall totals of 50-150 mm possible."

Daydream Island is without water on Wednesday morning, with around 200 holidaymakers and 100 staff stranded at the island's sole resort without toilets, taps and drinking water.

The Premier said that getting water and other aid to the island was a "priority" in a press conference on Wednesday morning.

The tiny tropical paradise has widespread damage following Cyclone Debbie -- the island's only resort has damage to its atrium, boardwalk and sections of its accommodation, the jetty and pontoons were damaged and two of the three iconic mermaid statues have been swept away.